Stress corrosion cracking (SCC) is a known phenomenon occurring in reactor components, such as structural members, piping, fasteners, and welds, exposed to high-temperature water. The reactor components are subject to a variety of stresses associated with, e.g., differences in thermal expansion, the operating pressure needed for the containment of the reactor cooling water, and other sources such as residual stress from welding, cold working and other inhomogeneous metal treatments. In addition, water chemistry, welding, heat treatment, and radiation can increase the susceptibility of metal in a component to SCC.
Stress corrosion cracking has been found in the shroud girth seam welds or heat affected zones of the core shroud. This diminishes the structural integrity of the shroud, which vertically and horizontally supports the core top guide and the shroud head. Thus, there is a need for a method and an apparatus for repairing a shroud which has cracks in or near the shroud girth seam welds.